Right, a famous bronze vessel with gilded rider, from the collection of the Yunnan Provincial Museum in Kunming, China, considered an icon of the Dian culture, Western Han Dynasty (206 B.C. to A.D. 24).

Below, a piece from a Thesaurus Fine Arts catalog. Its caption calls it "a rare gilt-bronze vessel" typically dated to Western Han but in this case "believed to belong to Tang, a much later period." (The Tang Dynasty was A.D. 618-907.)

Chinese art experts say the Thesaurus piece is a copy  and not a very good one. Craftsmanship and gilding are among the many details that set the two pieces apart.

The Thesaurus piece is "an amalgam, and it's not a Tang amalgam," says John Stevenson, former acting associate curator of Chinese art at the Seattle Art Museum. "When you have contradictory elements, dating from centuries apart, on a single piece, that piece is wrong. Bad workmanship and plain ugliness are other factors."